~258868 1164-116 SIIORT-~CTIN~ ESTER-CONT~ININ~l BETA-A[)RENFRGIC
GG:~70 BLOCKING COMPOUNDS, ~ND P~OCESS FOR M~KING SAME
~ack~rol!nd of the Inventlon The present invention relates to B-adrenergic blocking compounds useful in the treatment or prophylaxis of cardiac disorders.
The therapeutic and prophylactic uses of compounds which block sympathetic nervous stimulation of ~-adrenergic receptors in the heart, lungs, vascular system and other organs are well documented.
Typically, such compounds are administered therapeutically to patients suffering from ischemic heart disease or myocardial infarction for the purpose of reducing heart work, i.e., heart rate and contractile force. Red~ucing heart work reduces oxygen demand, and may also actually increase oxygen supply. Thus reducing heart work can aid in the prevention of further tissue damaqe and can relieve angina pectoris.
~-Adrenergic stimulation may also agyravate or cause arrhythmias because of increased levels of catecholamines. Thus B-blocking agents may be employed to reduce the risks of arrhythmias.
Compounds have been discovered which selectively block B-adrenerqic receptors in various organs. Beta receptors in the heart are generally referred to as ~I receptors, and those associated with vasodilation and bronchodilation are ~2 receptors. Selective ~-blockers are preferred for the treatment of cardiac disorders, because they may have less potential to cause hypertension or
-2~ 5~36~
bronchoconstric~ion. A number of ~1 selectlve adrenergic blocking agents have been discovered. Smith, L. H., YL_?~E~__52o~L IL~O:~ ~OOL~
28, 201-212 (1978). Most of such compounds are structural variations of 1-amino-3-aryloxy-2-propanol.
Heretofore, the emphasis in ~-blocker research has been to develop compounds which can be administered to cardiac patients over long periods of time. However, often it is desirable in the critical care setting to quickly reduce heart work or improve rhythmicity during a cardiac crisis, e.g~, during or shortly after a myocardial infarc-tion. Conventional ~blocking agents can be employed for such treat-ment, but their duration of action may be much longer than desired by the physician. A ~-blocking agent possessing a long duration of action does not allow precise control of heart work or prompt reversal of the ~-blocking effect, which may be required in a critical care setting.
For instance, if heart output becomes dangerously low, it is desirable to quickly reduce or eliminate ~-blocking activity. The lingering activity of available ~-blocking agents can be counterproductive and can greatly complicate the therapeutic decisions required of the physician during such critical care of cardiac patients.
Accordingly, there is a need for a pharmaceutical preparation and method of treatment, employing a ~-adrenergic blocking agent having a short duration of action.
5umma~ of the Invention In accordance with the present invention, disclosed herein is a method for the treatment of prophylaxis of cardiac disorders in a mammal comprising administering to such mammal a short acting compound of the formula:
O OH
ROC - (CH2)n - Ar-O-CH2-CH-CH2-NH-R
x wherein R is lower alkyl, lower cycloalkyl, lower alkenyl, lower alkyl or aryl carboxymethyl, lower haloalkyl, aralkyl or aryl; n is an integer from O to about 10; x is an integer from 1 to 3, provided that when x is o greater than 1, different occurances of the R-O-C-(CHz)n ~ group may be the sæme or dlf~erent; Ar ~s unsubstituted aromatic or aromatlc substi-tuted with lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy, halogen, acetamido9 amino, nitro, lower alkylamino, hydroxy, lower hydroxyalkyl or cyano; Rl is lower alkyl, or aralkyl, or a pharmaceuti-cally acceptable sale thereof.
Detailed Description of the Invention Compounds adminlstered by the method of the present invention are represented by the formula:
_ O OH
ROC - (CH2)n ~ ~ - Ar-O-CH2-CH-CH2-NH-R
x wherein R represents lower alkyl of straight or branched carbon chains from 1 to about 10 carbon atoms, lower cycloalkyl of from 1 tc about 5 carbon atoms, lower alkenyl o~ from 2 to about 5 carbon atoms, lower alkynyl of from 2 to about 5 carbon atoms, lower alkyl carboxymethyl in which the alkyl portion contains from 1 to about 5 carbon atoms~ aryl carboxymethyl in which the aryl portion contains from 6 to about 8 carbon atoms, lower haloalkyl of from 1 to about 5 carbon atoms, aryl of from 6 to about 10 carbon atoms or aralkyl wherein the alkyl portion cortains from about 1 to about 5 carbon atoms and the aryl portion represents substituted or unsubstituted monocyclic or polycyclic aroma-tic or heterocyclic ring systems of from 6 to about 10 carbon atoms; n represents an integer from O to about 10~ x represents an integer from 1 to 3, provided that when x is greater than 1, different occurances of o the R-O-C(CH2)n group may be the same or different; Ar represents sub-stituted or unsubstituted aromatic, including monocyclic, polycyclic and heterocyclic ring systems, wherein aromatic substituents include lower alkyl of from 1 to about 10 carbon atoms, lower alkenyl or from 2 to about 10 carbon atoms, lower alkynyl of from 2 to abaut 10 carbon atoms9 lower alkoxy of from 1 to about 10 carbon atoms, halogen, acetamido, amino, nitro, lower alkylamino, of from 1 to about 10 carbon atoms, hydroxy, lower hydroxy alkyl of from 1 to about 10 carbon atoms, and cyano; R1 represen~s lower alkyl of from 1 to about 10 carbon atoms9 4 ~2588~i8 ~
such as methyl, propyl, hexyl, isopropyl, and the llke; or aralkyl wherein the alkyl portion contains from 1 to about 5 carbon atoms and the aryl portion contains from 6 to about 10 carbon atoms, such as ben~yl, phenethyl, naphthylethyl, 3,4-dimethoxyphenethyl and the like.
5 Such compounds may be administered as their pharmaceutically acceptable acid addition salts9 e.g., as the hydrochloride, sulfate, phosphate, g1uconate, tartrate, etc.
P ~ icularly suitable ox~unds ~re of the formula _ _ O OH
ROC-(CH2~n- - - Ar-O-CH2-CH-CH2NH-R
_ _ x wherein R is lower alkyl, lower cycloalkyl, lower alkenyl, lower alkyl or aryl carboxymethyl, lower haloal~yl, or aralkyl; n is an integer from 1 to about 10; x is an integer from l to 3, provided that when x is greater than 1, different occurrences of the O
R-O-C(CH2)n-group may be the same or different; Ar is unsubstituted aromatic or aromatic substituted with lower alkyl, l~wer alkenyl, lower alkynyl, lower alkoxy, halogen, acetamido, amino, ni~ro, lower alkylamino, hydroxy, lower hydroxyalkyl, or cyano; Rl is lower alkyl or aralkyl and pharmaceutically acceptable salts thereof In preferred compounds, n is an integer from O to about 5, and x is 1 or 2, and in particularly preferred compounds, Ar is phenyl, x is 1 or 2 and n is an integer from O to about 3~ It has been found that the compounds in which Ar is phenyl and para-substituted, ~-blocking potency and shortness of duration of action are improved when n is at least 1, i.e. the ester group is isolated from the aromatic ring by at least one methylene unit. Alternatively, in compounds in ~hich Ar is ~ ~58~6~3 o phenyl, at least one of the ester-contalnlng groups, R-0-C-, is advantageously in the ortho-positlon with respect to the slde chain. It is surprising and presently unexplained9 that two configurations of the compounds of the present lnventlon, para-substitution with an ester carbonyl isolated from the aromatic ring and ortho-substitution with the ester carbonyl attached directly to the aromatic ring, provide enhanced ~-block~ng potency and relatively short duration of action.
In preferred compounds, the ester substituent, R~ is lower alkyl of from 1 to about 5 carbon atoms, such as methyl, ethyl, n-butyl, lo n-pentyl, and the like; lower alkenyl of from 2 to about 5 carbon atoms, such as ethyl, 2-propenyl, 2-methyl-3-butenyl and the like, or lower cycloalkyl of from 3 to about 5 carbon atoms such as cyclopropyl, cyclopentyl, 2-methylcyclopropyl, and the like; R1 is lower alkyl of from 1 to about 5 ~arbon atoms such as methyl, ethyl, propyl, t-butyl, lS pentyl and the like, or aralkyl, wherein the alkyl portion contains from 1 to about 5 carbon atoms and the aryl portion contains from 6 to about carbon atoms, such as benzyl, phenethyl, dimethoxyphenethyl, naphthylethyl, phenylbutyl, and the like.
Aromatic substituents include lower alkyl of from 1 to about 5 carbon atoms, lower alkenyl of from 2 to about 5 carbon atoms, lower 1~588~
alkoxy of ~rom 1 ko about S carbon atoms, halogen, acetamido, am~no, n~tro, lower alkylamino of from 1 to about 5 carbon atoms, hydroxy, lower hydroxyalkyl of from 1 to about 5 carbon atoms, and cyano.
Pre~erred aromatic subst~tuents are lower alkyl of from 1 to about 5 carbon atoms, fluoro, chloro, and alkyl.
The compounds described herein may be prepared by any suitable procedure. The compounds are advantageously prepared by reacting an appropriate phenol derivative with epichlorohydrin in the presence of a base to form a 1,2-epoxy-3-aryloxypropane derivative according to the following reaction:
~ O ' O
ROC - (CH2)n - - Ar-OH + cl-CH2-CH-~ 2 x ~ [ ROC - (CH2)n ~ Ar-O-CH2-CH-CH2 wherein Ar, R, n, and x are defined as above. The 1,2-epoxy-3-aryloxy-propane so prepared may then be reacted with an amine to form the desired product:
. O
O ~\
ROC - (CH2)n Ar-o-cH2-GH-cH2 + R1-NI~2 x ~ ROC - (CHz) ~ Ar-O-CH2-CH-CH2:H-R
6 ~258868 -This reaction ~s preferably conclucted ~n an alcoholic solven~
identical to the ester adduct to prevent alcoholysis side reactlons, e.g. when R ~s methyl, the reaction solvent is preferably methanol.
The phenol derivatives used as startlng materials in the reaction scheme described above are generally commercially available compounds or may be prepared by methods known in the art. For instance, for the preparation of some preferred compounds of the present invention, suit-able starting materials include methyl 2-hydroxybenzoate, methyl (4-hydroxyphenyl) acetate, methyl 4-hydroxyphenyl propionate, and the like.
The compounds of this invention are advantageously administered parenterally, e.g., by intravenous injection or intravenous infusion.
Formulations for intravenous injection preferably include the active compound as a soluble acid addition salt in a properly buffered isotonic solution.
The dosage administered to a patient and the duration of infusion will depend upon the patient's needs and the particular compounds employed. For short periods of infusion, eOg. less than about three hours, the duration of effect is thought to be determined by both metabolic effects and distribution phenomena. For relatively long periods of infusion, e.g. greater than about three hours, the duration of effect is thought tG depend largely on metabolic effects.
Accordingly, although the present methods and compounds are generally useful for short term infusion therapy, certain compounds are preferred for longer durations of infusion. This principle is demonstrated by reference to the 40 minute and three hour infusion studies described in Examples XXXVI-LI~ The compounds have been found to be generally non-toxic within conventional dosage ranges. Dosages of about 0.001 to about 100 mg. per kg. of body weight per hour are generally employed, with preferred dosages ranging from about 0.01 to about 10 mg. per kg.
of body weight per hour.
The present invention is further illustrated by the following examples which are not intended to be limiting.
-7- gL~5~3~36~3 EXAMPLE I
This example describes the experimental procedure for producing the following compound:
OH
O-CH2-CH CH2-NH-CH(CH3)2 O ~ ~HCl Ch30-C
A mixture of 15.2 gm (0.1 mole) oF methyl 4-hydroxybenzoate, 27.6 sm (0.2 mole) potassium carbonate and 31 mL(0.4 mole) epichlorohydrin in 250 mL acetone was heated to reflux for 24 hours. The reaction medium was then filtered and evaporated. The residue was taken up in 100 mL toluene and washed with 100 mL 1.0 N NaOH and 2xlOOmLwater. The toluene phase was then dried over magnesium sulfate and evaporated to provide the crude product as an oil. Purification was effected by vacuum distillation (66-67; 75 u pressure) and provided 14 gm (67%) of a clear o;l when gradually crystallized at room temperature: mp 54-55C. The NMR and IR spectra and elemental analysis data were consistent with the assigned structure.
Methyl 4-[2-Hydroxy 3 ~oprop~lamino)propoxy]benzoate Hydrochloride A mixture of 2.1 gm (0.01 mole) of the epoxide derivati~e described above and 0.9 mL (0.01 mole) -of isopropylamine in 25 mL of methanol was heated to reflux ~or 2 hours. The reaction medium was evaporated to a clear oil which was then taken up in methanol and treated with ethereal HCl. Crystals formed at room temperature and provided 1.25 gm (41%) of product having a melting point of 168-169C.
The NMR spectrum was consistent with the assigned structure and the elemental analysis was consistent with the molecular formula C14H22Cl N04.
EXAMPLE II
This example describes the experimental procedure for producing the following compound:
-8- ~L~5~3~36~3 OH
,¢~, O-CH~ -CH -CH2 -NH CH ( C 13 ) 2 _thy! 4-(2,3-Epox~ypropoxy~benzoate A mixture of 16.7 gm (0~10 mole) of ethyl 4-hydroxybenzoate, 20.7 gm (0.15 mole) of potassium carbonate and 24 mL (0.30 mole) of epichlorohydrin in 250 ~L acetone was heated to re~lux ~or 12 hours.
The reaction medium was then filtered and evaporated. The resultlng oil was taken up in 100 mL toluene and washed with 100 mL 1.0 N sodium hydroxide and 2xlOO mL water. The toluene phase was then dried over magnesium sulf2te and evaporated to give 13.5 gm (61%) of a clear oil.
The NMR spectrum of this oil was consistent with the assigned structure and the oil was used in the next reaction step without further purifica-tion.
Ethyl 4- [? -H~droxy-3-~isopropylamino)pro~oxy~benzoate Hydrochloride A mixture of 2.2 gm (0.01 mole) of the epoxide derivative prepared as described above and 25 mL (0.28 mole) of isopropylamine in 25 mL of ethanol was heated to reflux for 2 hours. The reaction medium was then evaporated to a clear oil which was dissolved in ethanol and treated with ethereal HCl. The white crystals which were produced (1.07 gm, 35%) had a melting point of 112-114C. The NMR spectrum was consistent 25 with the assigned structure and the elemental analysis was consistent with the molecular formula Cl5H24C1 N04.
EXAMPLE Ill This example describes the experimental procedure for producing the following compound:
OH
~ OCH2-CH-CH2-NH-CH(CH3)2 . HCl CH30-C CH2 ,,~J
9- ~2s~
A solution of 15 gm (0.1 mole) oF 4 hydroxyphenylacetic acid in 500 mL methanol and 2 mL concentrated sul~uric acid was placed in a Soxhlet extractor charged with 3A molecular sieves. The solution was heated to reflux for 72 hours, and the sieves were exchanged at 24-hour intervals. The reaction medium was then evaporated to an oil which was dissolved in 100 mL toluene and extracted with 3x100 mL water. The toluene phase was dried over magnesium sulfate, treated with activated charcoal and evaporated to provide 13 gm (80% yield) of a yellow oil.
The NMR spectrum was consistent with the assigned structure and this material was used in the next reaction step.
Methyl 4-t2,3-Epox~propoxy)phenylacetate The oil described in the preceding reaction was utilized directly in the condensation reaction with epichlorohydrin, potassium carbonate and acetone as described in Example I to provide the desired aryl ether epoxide in 60% yield. The NMR spectrum of the clear oil obtained in this manner was consistent with the assigned structure.
Methyl 4-~2-Hydrox~-3-(isoprop~lamino)propoxy]phenylacetate hydrochloride A mixture of 2.2 gm (0.01 mole) of methyl 4-(2,3-Epoxypropoxy3-phenylacetate and 1.7 mL (0.02 mole) o~ isopropylamine in 25 mL methanol was heated to reflux for 2.5 hours. The reaction medium was then eYaporated, and the resulting oil was dissolved in methanol and treated with ethereal HCl to provide 0.6 9 (19%) of white crystals: mp 119-121. The NMR spectrum was consistent with the assigned structure and the elemental analysis was consistent with the molecular formula Cl 5H24N04C 1 -EXAMPLE IV
This example describes the experimental procedure for producing the following compound:
-10~ S886~3 0~1 0 ~ 0-CH2-CH-CH2-NH-CH(CH3)2 CH30-C CH2CH2 ~
.HCL
Methyl 3-(4-Hydroxyphenyl)propionate A solution of 17 gm (0.1 mole) of 3-(4~hydroxyphenyl) propionic acid in 500 mL methanol and 2 mL concentrated sulfuric ac~d was placed in a Soxhlet extractor charged with 3A molecular sieves. The solution was refluxed for 72 hours and the sieves were exchanged at 24 hour intervals. The reaction medium was then evaporated to an oil which was dissolved in 100 mL toluene and extracted with 3x100 mL water. The toluene phase was dried over magnesium sulfate, treated with activated charcoal and evaporated to provide 15 sm (80%) of a clear oil. The NMR
spectrùm was consistent with the assigned structure and this material was utilized directly in the next reaction step.
Methyl 3-~4-(~,3-Epox~eropoxy)~he yl]propionate The oil described above was utilized directly in the condensation reaction with the epichlorohydrin, potassium carbonate, and acetone as described in Example I. Purification was effected by vacuum distilla-tion (1S6; 0.4 mm pressure) and provided the aryl ether epoxide in 45%
yield. The NMR spectrum of the clear oil obtained by this procedure was consistent with the assigned structure and the elemental analysis was consistent with the molecular formula C13H1604Cl.
Methyl 3-~4-[2-Hydroxy-3~ pro~lamino~eropoxy]phenyl]propionate Hydrochloride A mixture of 50 gm (0.21 mole) of methyl 3-~4-(2,3-epoxyproxy)-phenyl~ propionate and 100 ~L of isopropylamine in 100 mL methanol was heated to reflux for 4 hours. The reaction medium was then evaporated and the resulting oil taken up in methanol and treated with ethereal HCl and provided crystals which were recrystallized in similar fashion to provide 28 gm (47%) of white crystals: mp 85-86. The NMR and IR
spectra and the elemental analysis data were consistent with the assigned structure having a molecular formula of C16H26N04Cl.
~ L~S~38 6 EXAMPLES V - VII
These examples describe procedures for preparing the compounds identified in Table r. The procedure of Example IV was repeated in all essent~al details, except ~he amine reactant listed in Table I was substitued for isopropylamine. The NMR and IR spectra and elemental analyses of each of the compounds so prepared conformed to the assigned structure.
TABLE I
. 10 CH3-0-C-(CH2)2 - ~ 0-CH2-CH-CH~-NH-R1 Amine Melting 15 Exame~ Reactant Rl-NH2 Rl Point _ V t-butyl~mine t-butyl 144-146C
VI 3,4-dimethoxyphen- 3,4-dimethoxy- 138-140C
ethylamine phenethyl VII benzylamine benzyl 180-181C
EXAMPLE VIII
This example describes experimen~al procedures for preparing the following compound:
OH
O-cH2-CH-cH2-NH-~(cH3)3 O J~
Methyl 4-~2-Hydroxy-3-(t-butylamino)propoxy]benzoate A mixture of methyl 4-(2,3-epoxypropoxy~ benzoate (prepared as described in Example I) (2.19, 0.01 mole), 10 mL of t-butylamine and 10 mL of methanol was heated to reflux for three hours. The reaction medium was then evaporated under reduced pressure to provide the amine as an oil. The free amine was crystallized from hexane ethyl acetate in 12- 125~386~
65% yield: m.p. 88-89C. The NMR spectrum and elemental analysls were consistent with the assigned structure.
Ç~L~
These examples describe the preparation of the following compounds:
Example IX
OH
o-cH2-cH-cH2-NH-c~l(cH3)2 ~ C-OCH3 Example X
OH
O-CH2-CH-CH2-NH-C(CH3)3 ~ C-OCH3 o Example XI
O-CH2-CH-CH2-NH-CH2-CH2 ~ CH3 ~ C-OCH3 CH3 Methvl 2-(2~3-Epoxypropoxy)benzoate A mixture of 15.2 9 (0.10 mole) of me~hyl 2-hydroxybenzoate, 27.6 9 (0.20 mole) of K2C03 and 31 mL (0.40 mole) of epichlorohydrin in 250 mL of a~etone was hcated to reflux for 24 hours. The reaction medium was then filtered and evaporated under reduced pressure. The resulting oil was dissolved in 100 mL toluene and washed consecutively with 100 mL
water, 2x100 mL 1.0 N NaOH, and 2x100 ml. water. The organic phase was then dried over MgSO4 and evaporated under reduced pressure to provide the crude product as an oil. Purification was effected by vacuum distillation to provide an oil in 12% yield: boiling point 148C (75u).
The NMR and IR spectra and elemental analysis were consistent with the assigned structure.
Methyl 2-[2-Hydroxy-3-(isoprop~lamino)propoxyJbenzoate (Example_IX~
A mlxture of 2.1 9 (0.01 mole) of methyl 2-(2,3-epoxypropoxy) benzoate, 100 mL of isopropylamine and 10 mL of methanol was heated to reflux for three hours. The reaction medium was then evaporated under reduced pressure to provide the amine as an oil. The oil was treated with hexane: ethyl acetate (9:1) to generate the free amine as a crystalline product in 63% yield: m.p. 78-79C. The NMR spectrum and elemental analysis were consistent with the assigned structure.
Meth~ 2-[2-Hydroxy-3-(t-butylami_o)propoxy~benzoate Hydrochloride H~mihydrate (Example X) This material was prepared by the same reaction used for the compound of Example IX except that t-butylamine was substituted for isopropylamine and the crystalline hydrochloride salt was prepared in 30% yield by adding aqueous HCl to a methanolic solution followed by trituration with ether: m.p. 116-118C. The NMR spectrum and elemental analysis were consistent with the assigned structure.
Methyl 2-~2-Hydroxy-3-(324 dimethoxypheneth~lamino)propoxylbenzoate Oxalate ~Example XI) This material was prepared by the same reaction used for the compound of Example IX except that 3,4-dimethoxyphenethylamine was sub-stituted for isopropylamine, and the product was crystallized as its oxalate salt from methanol-ether in 25% yield: m.p. 125-126C. The NMR
spectrum and elemental analysis were consistent with the assigned structure.
12~8~6 EXAMPLE XII
This example describes procedures for produc~ng a compound of the formul a CH3-CH2-CH2-O-c-(cH2)2 ~ 0-cH2-cH-cH2-NH-cH(cH3)2 .HCl A solution of 15 9 (.09 mole) of 3-(4-hydroxyphenyl)propion;c acid in 250 mL of n-propanol containing 5 drops of conc. H2S04 was heated to reflux for 72 hr in a Soxhlet Extractor charged with 50 9 of 3A molecular sieves. The reaction medium was then evaporated under reduced pressure and the resulting oil dissolved in 100 mL toluene and washed with three 50 mL portions of water. The toluene phase was then dried with MgS04 and evaporated under reduced pressure to provide 12 9 (64%) of a clear oil which was utilized directly in the next step without additional purification. The NMR spectrum was consistent with the assigned structure.
n-Propxl 3-~4-(2,3-Epox~propox~phenyl]propionate A mixture of 9 9 (0.04 mole) of n-propyl 3-~4-hydroxyphenyl) propionate, 10 9 (0.08 mole) of K2C03 and 12 mL (0.15 mole) of epichlorohydrin in 150 mL of acetone was stirred and heated to reflux for 20 hours. The reaction medium was then filtered and evaporated under reduced pressure. The resulting oil was ~aken up in 100 mL
toluene an~ washed consecutively with 50 mL water 2x50 mL of 1 N NaOH
and 2x50 mL of water. The toluene phase was then dried over MgS04 and evaporated under reduced pressure to provide 3 9 ~30%) of a clear oil which was used directly in the next step without additional purifica-tion. The IR and NMR spectra of the reaction product were consistent with the assigned structure.
1~886 ~9 A solution of 1.5 9 (0.006 mole) of n-propyl 3-[4-(2,3-epoxy-propoxy) phenyl] propionate in 10 mL of isopropylamine and 20 mL o~ n-propanol was heated to reflux for 4 hours. The reaction medium was then evaporated under reduced pressure to provide the crude free amine as an oil. The oil was dissolved in n-propanol and treated with ethereal HCl and provided 102 9 (56%) of white crystals: mp 88-92C. The NMR
spectrum of the product was consistent with the assigned structure and the elemental anal ys i s data was consistent w~th the molecular formula EXAMPLE XIII
The experiment of Example IV was repeated in all essential details to produce a compound of the formula OH
0-CH2-CH-CH2-NH-C~l(cH3)2 l ll (COOH)2 . 1/4 H20 ~ O
~CH~)2-C-0 CH3 except that 3-(2-hydroxyphenyl)propionic acid was substituted for 3-(4-hydroxyphenyl)propionic acid, and the final product was crystallized as its oxalate salt from methanol-ether. The product melted at 92-94C and NMR spectrum and elemental analysis were consistent with the assigned structure.
EXAMPLE XIV
This example describes procedures for producing a compound of the formula CH2=CH-CH2-0-C--~o-cH2-cH-cH2-NH-cH(cH3)2 16~ ~2S~38~j~
3-Propenyl 4-H,Ydroxybenzoate A m~xture of 27.6 9 (0.2 mole) of 4-hydroxybenzo~c acid, 13.8 9 (0.1 mole) of K2C03 and 24 9 (0.2 mole) of allyl bromide in 350 mL of acetone: H20 (9:1) was heated to reflux for 3 hours. The acetone layer was separated and evaporated to dryness in vacuo and the residue was recrystallized from CCl~ to give 19.7 9 (55%) of white crystals: mp 92-96, whose NMR spectrum was consistent with the assigned structure.
3 Propenyl 4-(2,3-Epoxm ropoxyLbenzoate The experimental procedure of Example I for preparing Methyl 4-(2,3-epoxypropoxy)benzoate was repeated in all essential details, except 3-propenyl 4-hydroxybenzoate was substituted for methyl 4-hydroxybenzoate. The reaction yielded a clear oil in 61% yield~ whose NMR spectrum conformed with the assigned structure.
3-Propenyl 4-[2-Hydroxy-3-(isopropylamino~ropoxy~benzoate The experimental procedure of Example I for preparing methyl 4-[2-hydroxy-3-(isopropylamino)propoxy~benzoate hydrochloride was re-peated in all essential details, except 3-propenyl 4-2a3(epoxypropoxy)-benzoate was substituted for methyl 4-(2,3-epoxypropoxy)benzoate.
Allyl alcohol was employed as the reaction solvent, and the reaction product was crystallized as the free amine from hexane: ethyl acetate (4:1) in apyroximately 25% yield. The product melted at 63-64C and its NMR spectrum and elemental analysis con~ormed to the assigned struc-ture.
EXAMPLES XV AND XYI
The procedures of Example XIV were repeated in all essentialdetails to produce the compounds identified in Table II, except that 3-hydroxybenzoic acid was substituted for 4-hydroxybenzoic acid as the starting materlal in Example XV and 2-hydroxybenzoic acid was substituted for 4-hydroxybenzoic acid as the starting material in Example XVI. 80th compounds were crystallized as their oxalate salts.
The NMR spectra and elemental analyses of the compounds were consistent with the assigned structures.
-17~ 5~8 TABLE II
Example Compound Melting Poin~
OH
XV O-CH~-CH-CH2-NH-CH(CH3)2 125-126 ~
C-O-CH2-CH=CH2 .(COOH)2 OH
XVI ~ O-CH2-cH-cH2-NH-cH(~H3)2 139-140 O
C-O-CH2-CH-CH2 (COOH~2 EXAMPLES XVII - XXXII
2n - -- _ Several of the compounds of the present invention were tested for ~-blocking activity in vitro using guinea pig right atria and guinea pig tracheal strips mounted in a tissue bath containing oxygenated (95% 2-5X C02) Krebs physiological salt solution a~ 37C. Each tissue was ; 25 suspended between a fixed glass rod and a Statham Universal Transducer connected to a Beckman recorder. Atria were allowed to beat spon-taneously under a loading tension of approximately 0.59. Changes in rate of response to isoproterenol, a standard ~-receptor agonist, were measured in the absence and presence of test compounds. Spiral strips of guinea pig trachea were suspended under 59 res~ing tension and incubated with phentolamine, tropolone, and cocaine. Active tension was generated by addition of carbachol (3.0 x 10 7M) and decreases in tension in response to isopoterenol were quantitated. Cumulative con-centration response curves were produced with isoproterenol both before and after 60-minute incubation of test compounds with atria and trachea~ Compounds with ~-blocking activity shifted concentration response curves to the right. The blocking potency of test compounds -18- 12S~3868 was estimated by computing PA2 values (-log KB) by the method of Furchgott (The Pharmacological Differentiation of Adrenergic Receptors., Ann. N.Y. Acad! Sci. 139:S53-570l 1967). Comparison of blockade of right atrial and tracheal response to isoproterenol permits assessment of cardioselectivity of test compounds; i.e., cardio-selective compounds are relatively more effective in blocking atrial rate than tracheal force responses to isoproterenol. The degree of cardioselectivity was estimated from ratio K8 trachea/KB atria 10(PA2 Atria -PA2 Trachea)- A ratio greater than one indicates cardio-selectivity, The results obtained with several of the test compounds are con-tained in Table III. All of the compounds are ~-blockers.
-19- 1 2 5~38 6 TABLE Ill Test Compound (Numerica1 Designation Indicat~s Previous Example Which Describes PA2 Preparation of Cardio-Exæmple _ Compound~ Atria Trachea selectivit.v XVII IV 7.0 5.6 30 XVIII V 6.5 5.9 4 XIX VI 6.5 5.2 20 XX VII 5.9 4.9 10 XXI XII 5.4 5.2 1.6 XXII XIII 8.6 8.9 0.5 15 XXIII III 6.4 5.4 10 XXIV XIV 6.3 5.7 4 XXV XV ~.9 7.2 2 : XXVI XVI 7.9 7.9 XXYII IX 8.2 7.9 2 20 XXVIII I 6.8 5.5 19 XXIX II 6.5 6.1 2.5 XXX X 8.8 8.9 XXXI VIII 6.5 5.4 32 XX~II XI 8.3 7.1 16 25 Propranolol 8.7 8.9 0.7 : Practolol 6.6 5.8 6 -20- 1;~5~ 8 EXAMPLE XXXIII
The duration of beta-blockade was determlned in VlVO uslng pento-barbital-anesthetized dogs instrumented for measurement of heart rate using a Beckman cardiotachometer triggered electronically by a phasic aortic blood pressure signal. Both vagus nerves were severed in the cervical region and the animals were mechanically ventilated. Two experimental designs were used. The first employed a 40-minute infusion of test compound and the second used a 3-hour infusion of test compound. In the 40-minute model, isoproterenol was infused into a foreleg vein at the rate of 0.5mg/kg/min to induce a beta-receptor mediated tachcardia. Various doses of test compound were then infused into a femoral vein over a period of 40 minutes. This infusion was then terminated and recovery from blockade was quantitated. The percent inhibition of the heart rate response to isoproterenol after 40 minutes of infusion of the test compound was computed along with the total cumulative doses received over ~he 40-minute period. This cumulative dose is expressed as mg/kg and is an indication of pot`ency. The time period required for 80% recovery of heart rate for each dose of test drug was also measured to quantitate duration of action. Potency and duration of action were normalized to a level of 50% inhibition of the isoproterenol response via least squares regression of data from each animal. Test compound were dissolved in 0.9% NaCl and inPused at a rate of 0.05 ml/kg/min or less. In the 3-hour infusion model, bo1us doses of isoproterenol (0.5gmlkg) were used to assess the degree of beta-blockade and recovery from beta-blockage after termination of the infu-sion. The doses were spaced at 10-minute intervals and were given before, during and following the infusion of test compounds. The infu-sion rate was adjusted so that the end of the 3-hour infusion period the degree of isoproterenol inhibition averaged about 50% of control. The results of the 40-minute infusion are shown in Table IV, and the results of the 3-hour infusion are shown in Table V.
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-23- ~L~S~38 6~3 EXAMPLE XLIX - LVII
These examples describe experiments which dernonstrate the dis-appearance of the compounds of the present invention ~n vitro in human whole blood, dog whole blood, and dog liver homogenate. The rate of disappearance of a compound is expressed as the half-life (T1/2), which is the time period in which one-half of the initial amount of compound tested disappears. In each experiment, lmL of a solution containing 5 ~9 of the test compound was added to 1 mL of whole blood or 1 mL of a 33%
(w/v) liver homogenate. The samples were incubated in a Dubnoff shaking metabo1ic incubator for 2.5, 5.0, 10.0, 20.0, 30.0 and 60.0 minutes at 37C. At the designated time periods, the test mixtures were removed from the incubator and transferred to a 0C ice bath. Acetonitrile (2 mL) was immediately added, and the mixtures were mixed to stop enzymatic hydrolysis. Zero time samples were prepared by adding 2 mL of acetonitrile to denature the proteins prior to addition of the test compounds. After centrifugation to sediment denatured proteins, 2 mL
of the supernatant was removed and analyzed by high pressure liquid chromatography, using a mobi1e phase of 60% acetonitrile/40% 0.05M
sodium phosphate buffer (pH 6.6), a U.V. detector, and a Waters u Bondapak Phenyl column. The half-life of each test compound was determined graphically by plotting the decrease in concentration as a function of time. The results of ~he experiments are shown in Table VI.
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